Video policy server

ABSTRACT

A system for distributing digital content includes two or more digital content sources. Each source has a separate session manager that is distinct from other session managers associated with other digital content sources. The system further includes at least one set of network resources that receive digital content from the two or more digital content sources, modulate the digital content onto a carrier signal suitable for transmission over an access network, and transmit the carrier signal over the access network. The system also includes a receiving device for terminating the carrier signal. The receiving device generates a digital content stream corresponding to the digital content from the two or more digital content sources. The system further includes a policy server for allocating bandwidth of the network resources to the digital content sources, and for monitoring a utilization state of the network resources.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of “VIDEO POLICY SERVER,” U.S.Non-Provisional patent application Ser. No. 11/041,779, filed Jan. 24,2005 which claims benefit of the following U.S. Provisional PatentApplications: “VIDEO POLICY SERVER,” U.S. Provisional Patent ApplicationSer. No. 60/538,803; filed Jan. 23, 2004 and, “POLICY BASED ADMISSIONCONTROL,” U.S. Provisional Patent Application Ser. No. 60/538,802, filedJan. 23, 2004, the entire contents of which are incorporated herein byreference.

BACKGROUND OF THE INVENTION

The present invention relates to content distribution over a network,and more particularly, to managing distribution resources forvideo-on-demand (VOD) and other content services on a cable network.

Video-on-demand, one of several services offered by cable multiplesystem operators (MSOs), enables a subscriber to customize cable contentaccording to their preferences and/or schedules. A typical VODdistribution architecture 10, shown in FIG. 1, includes a VOD server 12and a session manager 14, a number of edge quadrature amplitudemodulation (QAM) interfacing devices 16, a cable access network 18, anda set top box (STB) 20.

The VOD server 12 hosts a large volume of digital video content.Portions of this content may be selected via a request from thesubscriber. (i.e., the end user). The session manager 14 is responsiblefor setting up a video session, i.e., processing requests from thesubscriber and providing an interface between the VOD server 12 and theother components in the distribution architecture 10. The VOD server 12and the session manager 13 are typically tightly coupled and sold as aset.

The edge QAM interfacing devices (edge QAM) 16 receive digital videocontent from the session manager 14, QAM-modulate and up-convert thecontent, then transmit resulting QAM signal onto the coaxialinfrastructures within the access network 18.

The STB 20 terminates the QAM signals at the site of the subscriber andextracts the VOD content stream. The STB 20 then generates an outputsignal suitable for the subscriber's video equipment (e.g., televisions,recording devices, etc.).

In operation, the subscriber requests content (e.g., a movie, a naturedocumentary or a classic sporting event) via the STB 20. The STB 20conveys the request to the session manager 14. The session manager 14allocates suitable bandwidth resources in the edge QAM 16, and instructsthe STB 20 to tune to the appropriate frequency spectrum for thoseresources. The session manager 14 then directs the VOD server 12 tobegin streaming the appropriate digital content to the edge QAM 16, andthe edge QAM 16 translates the digital content to the appropriatefrequency spectrum.

One disadvantage of this architecture is that the edge QAM 16 isstatically mapped to a particular session manager/VOD servercombination, and cannot be shared with another session manager. Thesession manager 14 in FIG. 1 monitors and controls the resourceallocation of the edge QAM 16 for VOD content to multiple subscribers. Asecond session manager/VOD server combination cannot share the edge QAM16 because different session managers cannot communicate to coordinatethe edge QAM resources.

For example, if a cable MSO desires to deploy a second VOD server 22(and associated session manager 24) for hosting content different thanwhat is on the first VOD server 12, the second VOD server 22 mustdeliver its content via different edge QAM 26 than that used by thefirst VOD server 12, as shown in FIG. 2. This arrangement represents ahighly inefficient use of network resources.

SUMMARY OF THE INVENTION

In one aspect, a system for distributing digital content includes two ormore digital content sources, each having a separate session managerthat is distinct from other session managers associated with otherdigital content sources. The system further includes at least one set ofnetwork resources for receiving digital content from the two or moredigital content sources, for modulating the digital content onto acarrier signal suitable for transmission over an access network, and fortransmitting the carrier signal over the access network. The system alsoincludes a receiving device for terminating the carrier signal andgenerating a digital content stream corresponding to the digital contentfrom the two or more digital content sources. The system furtherincludes a policy server for monitoring a utilization state of thenetwork resources, and for allocating a set of bandwidth segments of theat least one set of network resources to the two or more digital contentsources.

The policy server allocates the bandwidth segments according to theutilization state of the at least one set of network resources.Alternatively, the policy server may allocate bandwidth according to aset of policy rules. Policy rules may define resource allocationaccording to subscriber priority, or they may define resource allocationaccording to a category of the digital content.

The receiving device includes a set top box for generating an outputsignal suitable for one or more subscriber video equipment components,and each of the two or more digital content sources includes avideo-on-demand server for providing video content.

The policy server issues instructions to the session manager associatedwith a digital content source to send video content to the at least oneset of network resources. In one embodiment, the policy server is avideo policy server for allocating the set of bandwidth segments of theat least one set of network resources to two or more video contentsources.

The utilization state includes information about how much bandwidth ofthe at least one set of network resources is allocated and how muchbandwidth of the at least one set of network resources is available.

In another aspect, a method of distributing digital content includesproviding digital content from two or more digital content sources, eachhaving a separate session manager that is distinct from other sessionmanagers associated with other digital content sources. The methodfurther includes receiving, at one or more sets of network resources,digital content from the two or more digital content sources. The methodalso includes modulating the digital content onto a carrier signalsuitable for transmission over an access network, transmitting thecarrier signal over the access network, and terminating the carriersignal and generating a digital content stream corresponding to thedigital content from the two or more digital content sources. The methodfurther includes allocating, with a policy server, a set of bandwidthsegments of the at least one set of network resources to the two or moredigital content sources, and for monitoring a utilization state of thenetwork resources.

In another aspect, a method of distributing digital content from acontent source to a receiving device over a network includes

-   -   sending an initiating request for digital content, from the        receiving device to a session manager associated with the        content source;    -   sending a resource request for network resources, from the        session manager to a policy server, as a result of the        initiating request;    -   evaluating and executing one or more policy rules to determine        whether or not the resource request should be granted;    -   sending an instruction from the policy server to the session        manager instructing the session manager to send digital content        to a specific set of network resources;    -   sending receiving information for receiving the digital content        to the receiving device; and,    -   sending digital content from the session manager to the network        resources.

The method further includes sending a notification from the policyserver to the network resources notifying the network resources of atransfer of digital content from the session manager to the networkresources. The network resources may include edge QAM interfacingdevices. The digital content may include video content, and the contentsource may include one or more video-on-demand servers.

The method further includes evaluating and executing the one or morepolicy rules to determine how much bandwidth of the network resourcesshould be allocated to the session manager.

BRIEF DESCRIPTION OF DRAWINGS

The foregoing and other objects of this invention, the various featuresthereof, as well as the invention itself, may be more fully understoodfrom the following description, when read together with the accompanyingdrawings in which:

FIG. 1 shows a prior art video-on-demand content distributionarchitecture.

FIG. 2 shows another view of the distribution architecture in FIG. 1.

FIG. 3 shows the content distribution architecture of the describedembodiment.

FIG. 4 shows a series of steps for setting up a video session using thearchitecture in FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The described embodiment is a cable network architecture in which avideo policy server (VPS) coordinates allocation of network resourcesamong two or more video-on-demand (VOD) servers each coupled to sessionmanagers (also referred to herein more generally as video contentsources). As used herein, the term “network resources” specificallyrefer to edge QAM resources, but in general, the network resources mayinclude any network components in the cable network architecture fromthe data source to the ultimate subscriber destination.

Although the described embodiment distributes video content across acable network, the concepts described herein also apply to thedistribution of more general digital content, such as video gamingcontent and other application data from two or more digital contentsources. Central to this distribution of digital content is a policyserver that allocates network resources to two or more digital contentsources based on various considerations such as the utilization state ofthe network resources and a set of policy rules governing the digitalcontent and the end consumers of the digital content (i.e., thesubscribers). This general architecture allows digital content sourcesto share network resources, where without this architecture, each ofthose digital content sources would be bound to a single set of networkresources.

In the described embodiment, the VPS takes on the resource allocationfunctionality that, for prior art architectures, typically resides inthe session managers associated with VOD servers. By abstracting theallocation functionality from the session managers and centralizing itin the VPS, the described embodiment allows multiple video data sourcesto utilize the same set of edge QAM interface devices.

FIG. 3 shows the described embodiment of a policy-based admissioncontrol scheme for use in a cable network architecture. A first VODserver 102, a second VOD server 104 and a third VOD server 106, eachaccompanied by an associated session manager (108, 110 and 112,respectively), host digital video content.

Each VOD server 102, 104 and 106 hosts a large amount of a particularcategory of video content. For example, the first VOD 102 server mayhost full length movie content, the second VOD server 106 may hostclassic sports content, and the third VOD server 106 may hostnature/wildlife content. Each VOD server merely streams selected videocontent when instructed by its associated session manager.

A session manager associated with each VOD server includes all of thefunctionality necessary for setting up and tearing down a video session.As used herein, a “video session” is transmission of video content fromone of the VOD servers, through the cable network, with the videocontent terminating at the location of the subscriber. The sessionmanager may be integrated into the VOD server, or it may be a separatecomponent either attached to, in close proximity to, or networked with,the VOD server.

Each VOD server/session manager can provide digital video content to aset of edge QAM interfacing devices 114 (referred to herein as “edgeQAM”). The edge QAM 114 modulates and up-converts the digital contentfrom the VOD servers, then transmits the resulting QAM signal onto thecoaxial infrastructures within an access network 116.

The edge QAM 114 is capable of providing a finite amount of throughputbandwidth for the digital content. In the described embodiment, thefirst VOD server 102, the second VOD server 104 and the third VOD server106 can share the throughput capacity of the edge QAM 114, so that eachVOD server can utilize one or more bandwidth segments of the overalledge QAM 114 throughput capacity. Each of the bandwidth segments can beany frequency width up to the total bandwidth of the edge QAM 114.

The STB 120 is a receiving device that terminates the QAM signals at thesite of the subscriber and extracts the VOD content stream from the QAMsignals. The STB 120 generates an output signal from the extracted VODcontent stream suitable for subscriber video equipment such astelevisions, video recorders and the like.

A video policy server (VPS) 118 controls how much throughput bandwidthof the edge QAM 114 each VOD/session manager uses. The VPS 118 monitorsthe utilization state of the edge QAM 114, i.e., how much bandwidth ofthe edge QAM 114 is currently being utilized, and how much of the edgeQAM 114 is available.

In order for a VOD server/session manager to transmit digital videocontent through the edge QAM 114, the session manager must request edgeQAM 114 resources from the VPS 118. The session manager specifies aparticular amount of edge QAM 114 resources depending upon the nature ofthe digital video content to be transmitted (e.g., high definitioncontent requires more bandwidth than ordinary video). The VPS 118evaluates the state of the edge QAM 114 to determine if the requestedresources are available. If those resources are available, and certainpolicy criteria are met, the VPS 118 admits the VOD server/sessionmanager to the requested edge QAM bandwidth. Once admitted, the VODserver/session manager begins streaming the digital video to the edgeQAM 114.

Once the VPS 118 allocates edge QAM bandwidth to a VOD server (forexample, the first VOD server 102), the VPS 118 removes that bandwidthfrom consideration for allocation to other sources. The VPS 118 thusinterprets the state of the edge QAM 118 as having its availabilityreduced by the amount of bandwidth allocated to the first VOD server102.

The allocated bandwidth remains unavailable until relinquished by thesourcing VOD server. The allocated bandwidth may be relinquished by, forexample, the expiration of a purchase period during which the subscribercan access the video, or a command from the session manager that thevideo data stream is complete. Once the bandwidth is relinquished, theVPS 118 considers that bandwidth available for allocation. As a result,the VPS interprets the state of the edge QAM 116 as having itsavailability increased by the amount of bandwidth relinquished.

As described above, the VPS 118 evaluates certain policy rules inaddition to resource availability before allocating resources to a videosource. Such policy rules allow for smooth integration of VOD with otherdata types within the network (e.g., high speed internet access,voice-over-IP, video conferencing, etc.). One type of policy may givepriority to certain data types. For example, policy rules may giveresource requests from certain data sources preferential treatment bygiving them higher priority access to the available resources. Further,policy rules can allow certain high priority data sources to preempt alower priority data stream that is currently using allocated resources.

Another type of policy may give priority to particular subscribers,creating a kind of “tier” system. For example, consider a three-tiersystem where the highest-priority tier is the ‘gold’ tier, the nexthighest priority tier is the ‘silver’ tier, and the lowest tier is the‘bronze’ tier. Policy rules involving subscriber tiers give preferentialtreatment to higher tiers, for which subscribers in those tiers pay apremium price. One exemplary tier-based rule may be:if ((subscriber_tier==bronze)&&(current_network_utilization>80%)) thenreject

With this rule, an allocation request for a bronze-tier subscriber willbe rejected if the current resource allocation is greater than 80percent. This and other tier-based policy rules thus function to biasnetwork availability towards the higher paying subscribers.

FIG. 4 illustrates a series of steps for setting up a video session andthe corresponding allocation of resources at the edge QAM 116. In thisexample, a subscriber requests, via the set top box (STB) 120, digitalvideo data from the second VOD server 104 and the associated sessionmanager 110. Although this example shows the steps for setting up asession from one particular VOD server and session manager, these stepsapply for a session with respect to any of the other VOD sources.

In the first step 130, the STB 120 requests particular VOD content fromthe session manager 110 associated with the relevant VOD server 104. TheSTB 120 determines which of the three is the relevant VOD server andsession manager based upon (i) configuration data within the STB 120 and(ii) the nature of the requested VOD content. In this exemplary case,the STB 120 sends the request to the second session manager 110 becauseits associated VOD server 104 hosts the particular type of VOD contentthe subscriber desires (e.g., a recently released movie).

In the second step 132, the session manager 110 sends a request to theVPS 118 for resource allocation (in this case, edge QAM 114 resources).This request includes information such as subscriber ID, subscriberservice tier, priority of the content, and streaming characteristics(e.g., constant bit rate/variable bit rate, bandwidth requirements,etc.).

In the third step 134, the VPS 118 evaluates and executes the policyrules defined by the MSO, while considering various factors, in order todecide whether to allocate network resources to the session manager 110.Such factors include the current utilization state of the networkresources, the service tier of the requesting subscriber, the nature ofthe content being requested, among others.

In the fourth step 136, the VPS 118 instructs the service manager 110 tosend the requested video content to a particular IP address and UDPport. This occurs only if the results of executing the policy rulesindicate such instruction is an appropriate action, and if sufficientnetwork resources are available. If the result of executing the policyrules indicate such instruction is an inappropriate action, the VPS 118does not respond to the service manager. Alternatively, the VPS 118 mayrespond to the session manager 110 with a message indicating the requestfor resource allocation has been denied.

In some cases, the network resources needed to fulfill the request fromthe subscriber will not be available, or the policy rules will not allowuse of the resources. In these cases the VPS 118 will not allocatenetwork resources to the session manager 110. Alternatively, the VPS 118may provide the service manager with alternatives such as using a lowerbit-rate stream or sending a request to another VOD server hostingsimilar content.

In the fifth step 138, the VPS 118 notifies the relevant edge QAM 114 toexpect the video data stream from the session manager 110 and to takeany necessary actions. Such actions may include converting the videodata to a lower bit rate, changing from constant bit rate to variablebit rate, or other processing actions unique to the incoming VODcontent.

In the sixth step 140, the session manager 110 communicates tuning andother information to the STB 120 necessary for receiving the requestedVOD content. Such information includes which frequency channel willcarry the video content, which MPEG program to monitor for a particularvideo stream, etc.

In the seventh step 142, the session manager 110 begins to stream therequested VOD content to the edge QAM 114, which converts the VODcontent stream to the appropriate format for viewing via the STB. TheQAM 114 modulates and up-converts the VOD content stream, then transmitsthe resulting QAM signal onto the coaxial infrastructures within anaccess network 116.

In some cases, the subscriber may choose to “pause” the video sessiondescribed above once the session is established, and the VPS 118 maytake different actions as a result depending on policy rules. Forexample, a subscriber may purchase a time slot (e.g., 24 hours) duringwhich the subscriber can watch the content as many times as he or shedesires. During this time slot, the subscriber may stop watching thecontent before it ends, assuming he or she will return later to watchthe remainder of the content. In this case, the service manager 110informs the VPS 118 of the interruption, and the VPS 118 may release thereserved resources until the subscriber resumes watching the content.Policy rules may, for example, dictate that those resources will not bereleased for higher-level subscriber tiers, so that the resources areguaranteed to be available for the entire time slot.

The above examples do not specify particular communication protocolsamong the various components. In general, any protocol appropriate forthe particular media and content may be used for the communicationdescribed above. Specific examples of communication protocols for theabove communications are listed below.

I) Communication between the STB 120 and the session manager 110:

1. DSMCC—(Digital Storage Media—Command and Control): See ISO/IECJTC1/SC29/WG11.

2. RTSP—(Real Time Streaming Protocol): See RFC-2326 (April 1998).

II) Communication between the session manager 110 and the VPS 118:

1. RTSP.

2. XML (eXtensible Markup Language).

3. HTTP (HyperText Transfer Protocol).

4. RSVP—(Resource reSerVation Protocol): See RFC-2205 (September 1997).

III) Communication between the VPS 118 and the edge QAM 116:

1. SNMP (Simple Network Management Protocol) See RFCs 1155, 1157, and1212 for SNMPv1 and RFCs 1441 through 1452 for SNMPv2.

2. XML.

3. HTTP.

Other aspects, modifications and embodiments are within the scope of theclaims.

What is claimed is:
 1. A system for distributing digital content,comprising: two or more video-on-demand digital content servers, eachhaving a separate session manager that is distinct from other sessionmanagers associated with other video-on-demand digital content servers,wherein each of the video-on-demand digital content servers comprises anetwork component; at least one set of network resources comprisingnetwork components that are separate from the network components of thevideo-on-demand digital content servers for (i) receiving digitalcontent from the two or more video-on-demand digital content servers,(ii) modulating the digital content onto a carrier signal suitable fortransmission over an access network, and (iii) transmitting the carriersignal over the access network, wherein the network resources includeedge quadrature amplitude modulation (QAM) interfacing devices; areceiving device for terminating the carrier signal and generating adigital content stream corresponding to the digital content from the twoor more video-on-demand digital content servers; a policy servercomprising a network component separate from the network components ofthe video-on-demand digital content servers and from the networkcomponents of the network resources for monitoring a utilization stateof the network resources, wherein monitoring the utilization state ofthe network resources includes monitoring the utilization state of theQAM interfacing devices, for receiving, from the video-on-demand digitalcontent servers, requests for allocation, and for allocating, inresponse to the requests and based on the utilization state, a set ofbandwidth segments of the QAM interfacing devices to the video-on-demanddigital content servers, wherein the policy server allocates the set ofbandwidth segments of the QAM interfacing devices to the video-on-demanddigital content servers in response to the utilization state of thenetwork resources indicating that previously allocated bandwidthsegments of the QAM interfacing devices are available.
 2. The system ofclaim 1, wherein the policy server allocates the bandwidth segmentsaccording to the utilization state of the at least one set of networkresources.
 3. The system of claim 1, wherein the policy server allocatesthe bandwidth segments according to a set of policy rules.
 4. The systemof claim 3, wherein the policy rules define resource allocationaccording to subscriber priority.
 5. The system of claim 3, wherein thepolicy rules define resource allocation according to a category of thedigital content.
 6. The system of claim 1, wherein each of the two ormore video-on-demand digital content servers includes a video-on-demandserver for providing video content.
 7. The system of claim 1, whereinthe receiving device includes a set top box for generating an outputsignal suitable for one or more subscriber video equipment components.8. The system of claim 1, wherein the policy server issues instructionsto the session manager associated with a video-on-demand digital contentserver to send video content to the at least one set of networkresources.
 9. The system of claim 1, wherein the policy server is avideo policy server for allocating the set of bandwidth segments of theat least one set of network resources to the two or more video-on-demanddigital content servers.
 10. The system of claim 1, wherein theutilization state includes information about how much bandwidth of theat least one set of network resources is allocated and how muchbandwidth of the at least one set of network resources is available. 11.A method of distributing digital content, comprising: providing digitalcontent from two or more video-on-demand digital content servers, eachhaving a separate session manager that is distinct from other sessionmanagers associated with other video-on-demand digital content servers,wherein each of the video-on-demand digital content servers comprises anetwork component; receiving, at one or more sets of network resourcescomprising network components that are separate from the networkcomponents of the video-on-demand digital content servers, digitalcontent from the two or more video-on-demand digital content servers;modulating the digital content onto a carrier signal suitable fortransmission over an access network; transmitting the carrier signalover the access network; terminating the carrier signal and generating adigital content stream corresponding to the digital content from the twoor more video-on-demand digital content servers; receiving, at a policyserver comprising a network component separate from the networkcomponents of the video-on-demand digital content servers and from thenetwork components of the network resources, requests from thevideo-on-demand digital content servers for resource allocation;monitoring, by the policy server, utilization state of the networkresources, wherein the network resources include edge quadratureamplitude modulation (QAM) interfacing devices, wherein monitoring theutilization state of the network resources includes monitoring theutilization state of the QAM interfacing devices; and allocating, by thepolicy server, in response to the requests from the video-on-demanddigital content servers and based on the utilization state, a set ofbandwidth segments of the QAM interfacing devices to the two or morevideo-on-demand digital content servers, and for monitoring autilization state of the network, wherein the policy server allocatesthe set of bandwidth segments of the QAM interfacing devices to thevideo-on-demand digital content servers in response to the utilizationstate of the network resources indicating that previously allocatedbandwidth segments of the QAM interfacing devices are available.
 12. Themethod of claim 11, further including allocating, using policy rules,the bandwidth segments according to the utilization state of the atleast one set of network resources.
 13. The method of claim 11, furtherincluding allocating, using policy rules, the bandwidth segmentsaccording to a set of policy rules.
 14. The method of claim 13, furtherincluding defining resource allocation according to subscriber priority.15. The method of claim 13, further including defining resourceallocation according to a category of the digital content.
 16. Themethod of claim 11, further including issuing instructions from thepolicy server to the session manager associated with a video-on-demanddigital content server to send video content to the at least one set ofnetwork resources.
 17. A method of distributing digital content from avideo-on-demand digital content server to a receiving device over anetwork, comprising: sending an initiating request for digital content,from the receiving device to a session manager associated with thevideo-on-demand digital content server, the video-on-demand digitalcontent server comprising a network component; sending a resourcerequest for network resources comprising network components separatefrom the network component of the video-on-demand digital contentserver, from the session manager to a policy server comprising a networkcomponent separate from the network component of the video-on-demanddigital content server and the network components of the networkresources; at the policy server, in response to the request from thevideo-on-demand digital content server, evaluating and executing one ormore policy rules to determine whether or not the resource requestshould be granted, wherein evaluating and executing one or more policyrules includes monitoring the utilization state of the network resourcesincluding the QAM interfacing devices, wherein the policy serverallocates at least one bandwidth segment of the QAM interfacing devicesto the video-on-demand digital content server in response to theutilization state of the network resources indicating that previouslyallocated bandwidth segments of the QAM interfacing devices areavailable; sending an instruction from the policy server to the sessionmanager instructing the session manager to send digital content to thespecific set of network resources; sending receiving information forreceiving the digital content to the receiving device; and sendingdigital content from the session manager to the network resources. 18.The method of claim 17, further including sending a notification fromthe policy server to the network resources notifying the networkresources of a transfer of digital content from the session manager tothe network resources.
 19. The method of claim 17, wherein the policyrules define resource allocation according to subscriber priority. 20.The method of claim 17, wherein the policy rules define resourceallocation according to a category of the digital content.
 21. Themethod of claim 17, furthering including evaluating and executing theone or more policy rules to determine how much bandwidth of the networkresources should be allocated to the session manager.
 22. A method foroperating a policy server, the method comprising: at a policy servercomprising a network component separate from network components ofvideo-on-demand digital content servers: receiving, from thevideo-on-demand digital content servers, requests for resourceallocation; monitoring a utilization state of network resourcescomprising network components separate from network components of thevideo-on-demand digital content servers and the network component of thepolicy server, wherein the network resources are associated withdelivering media content to terminating devices, wherein the networkresources include edge quadrature amplitude modulation (QAM) interfacingdevices, wherein monitoring the utilization state of the networkresources includes monitoring the utilization state of the QAMinterfacing devices; and allocating, in response to the requests andbased on the utilization state, bandwidth segments of the, QAMinterfacing devices to the digital content servers, wherein the policyserver allocates the bandwidth segments of the QAM interfacing devicesto the digital content servers in response to the utilization state ofthe network resources indicating that previously allocated bandwidthsegments of the QAM interfacing devices are available.
 23. The system ofclaim 1 wherein the policy server allocates the bandwidth segmentsutilizing policy rules that define resource allocation according to oneof a plurality of subscriber tiers.
 24. The method of claim 11 whereinallocating the bandwidth segments includes utilizing policy rules thatdefine resource allocation according to one of a plurality of subscribertiers.
 25. The method of claim 17 wherein the policy rules defineresource allocation according to one of a plurality of subscriber tiers.26. The method of claim 22 wherein allocating the bandwidth segmentsincludes utilizing policy rules that define resource allocationaccording to one of a plurality of subscriber tiers.